Heat exchange system



June 16, 1959 F.VDAUSKARDT- 3 3 HEAT EXCHANGE SYSTEM Fed April 14, 1953 3 Sheets-Sheet F'gf INVENTOR. Franz auskardt f 1959 F; DAUSKARDT &

HEAT EXCHANGE SYSTEM Filed April 14. 1953 3 Sheets-Sheet 2 a@ II a f Z l v u I i w i `I V" Y A i q 1 H 30 u T u H L' L .35 I

a i L ,vs z T Io f 26 INVENTOR.

Qarz (cuskardt BY mwau W June 16, 1959 F. DAUSKARDT &8 3

. HEAT EXCHANGE SYSTEM Filed April 14. 1953 3 Sheets-Sheet 5 INVENTOR. rcmz auskard MSN W United Sttes Patent fiFce *2896367 Patented June 16, 1959 i Application April 14, 1953, Serial No. 348,704 I Claims priority, application Germany April 13, 1952 3 Claims. c. 257-415 This invention relates to systems for heating liquids and more particularly to those comprising heat exchangers for heating liquids in the beverage industry, eg. beer and milk, and for similar purposes. The invention Will be described in connection with the pasteurization of milk, but only for illustrative purposes, it'pbeing understood that the inventon is not limited to use.

The pasteurizationof milk is carried out in systems comprisingseveral apparatus, of which a heat exchanger wheren the milk is pasteurized, a water heater, and a pumptor pumping the hot water through the heat exchanger, are the most important. Instead of water, steam may be used as the heating medium, but the use of steam has the drawback that parts of the milk may be` heated to such a high temperature that deleterious changes of some substances in these parts take place. Water is therefore preterred, and systems in which hot water is used are generally provided with a device for producing hot water. This device and the other parts of the system have heretofore been erected separately, the device for producing hot water often being located in the cellar or boiler room in the building in which the system is installed. This has several drawbacks. The piping is extensive and complicated, considerable space is required, and the erection of the different parts is expensive.

According to the present invention the aforementioned three parts, namely, the plate heat exchanger, the hot "water heater and the circulation pump, are built together in a closed unit. In order to make it clearly understood and readily carried into efiect, the invention will be described with reference to the accompanying drawings, in which Fig.1 is avschematic View of one form of the new system;

Figs. 2 and 3 are similar views of modified forms of the system, and

Fig. 4 is an enlarged sectional View of the three-way valve cock illustrated in Fg. 3.

According to Fig. 1, the water is heated by means of a steam ejector 1 and the pasteurzation of the milk takes place in the plate heat exchanger 2. The latter is connected to a water accumulator 3 so as to form a hot water circut in which the heating water, after having passed through the 'heat exchanger 2, is returned to the accumulator 3. The accumulator 3, which may have a small Volume Compared to the heat exchanger, is provided with an overflow pipe 4 through which condensate formed by the steam led into the ejector is discharged. This overflow pipe is directly attached to the rame formed by the water accumulator 3. A pump 5 for the circulation of the heating water is placed at the bottom of the accumulator and sucks the hot water directly from it. At ts lower end, the accumulator has walls 6a formin g a separate compartment 6 to accommodate the shaft 7 of a motor 10, which drives the pump 5. The motor is flanged to the frame formed by the hot 2 water accumulator 3. Water leakng from the packing box 8 flows from the bottom of compartment 6 through pipe 9 down upon the floor, upon which the unit is erected.

In order to compensate for the fluctuations occurring in the heating of the Water in the accumulator, a space 11 is provided between its overflow opening and its uppermost wall.

The heating Water and the milk to be heated are passed counter-currently through the heat exchanger 2, the main flow direction of the milk being indicated by the *broken line and that of the heating water being indicated by the full line. The cooled heating water from the heat exchanger 2 as well as steam are simultaneously fed into the steam ejector 1 where the water is heated to the required temperature. The heated water then passes through the accumulator 3, as shown generally by the broken line, to the sucton opening of the pump 5. It then flows through the heat exchanger 2 back to the steam ejector, thus commencing a new cycle.

According to Fig. 2 the heating of the water is carried out in heat exchanger l of the plate type. In the exchanger l the heat from the steam is transferred through the plates from one side to the other, where it is taken up by the Water flowing over the latter side. As in Fig. 1, the water accumulator is indicated at 3 and the milk heater at 2. 'Dhe main flow direction of the milk through heater 2 is also in this case represented -by the `broken line, while that of 'the water is represented by the full line. The use of a set of plates for heating the water not only allows a closed unit but also has the advantage that the plates can be used in various numbers in the heat exchanger 1 which can thus be adjusted to varying working conditions. By increasng the number of plates in heater l the heating effect will be higher, and vice versa. Plate heat exchangers also have the characteristc feature that the plates can easily be removed from the frame of the exchanger for cleaning. This is particularly advantageous for the heat exchanger in which the water is heated, since boler-scale may deposit on the plates, and if waste steam is used for heating, oil from this steam may gradually cover the heat transfer surfaces. the plates in the exchanger 1 are similar to those in the exchanger 2, so that the number of different plates will be minimized.

heat exchanger 2 passes by way of line 30` into the accumulator 3, then through this accumulator, as shown i generally by the broken line, to the inlet of pump 5, and then through line 31 to the plate heat exchanger 1 where it is heated by the steam 'entering from line 32, the steam condensate passing to the disoharge line 33. From plate heat exchanger 1 the hot water passes through connection 34 to the heat exchanger 2 Where it heats the milk entering and discharging at 35 and 36, respectively, the water then passing to the line 30 to repeat the cycle. Thus, the connecting lines 30 and 31 and the connection 34 comprise means interconnect-- ing the accumulator 3, pump 5, heat exchanger 1 and' plate heater 2 to form a closed circulation path for the Water.

In a unit 'made according to Fig. 1, a quantity of watercorresponding to the amount of steam fed into and con--` densed in the accumulator 3 will flow away through the pipe 4. Since the temperature of this Water is high, generally about 200 F., this means a considerable loss of heat. This loss can be avoided by the arrangement.` shown in Fig. 3, wherein a float is disposed in the ao-` cumulator and has its lever connected with a three-waw i Preferably, i I

am'ple, to; a; containr for feed water to the 'boiler froiii which 'steam is supplied to the ej ect'or '1.

'According toFig. '35 the lever 19 of fi'oat 1 2` is connected to the rotatable plug of a three-way valve cock 13.; to; which water from pl'ate heat eXchanger'Z is 'led through return piping 14 and' f-oin` which the 'main part:

of this? wateri normally led through* pipe 16 to' the ejector 1. The remaining water fed to cock 13 is led' away from-the water `circulatin system through a pi'pe 17'. to acOntainez (not shown )"fo`r feed water In order to maintain 'the 'atmos pher c pressure in the space' 11* above the watr surfacej'an opening is arranged in suit-able the top wallvof the accumulator 'or in other position in relation to this' surface;

' 'Dhe cock 13 is' shown in section on an enlarged scale J in Fi'g. 4. The plug 18 of' the 'cock is rigidly connected withl the float"lever 19 which is freely r'novab'le *with-' inia recess 20; in'the cock housing. i This housing also" has an inlet opening 22' to which the ppe 14 is con-" nected, an. outlet' opening 23 to 'which the pipe 16;s V connected, and 'an outlet opening 24 to which the pipe 17 i i's connected; When the' water level in the"ac'c'uni`'-' la'tor 3 sinks, the float lever 19 swings downwardly and thus 'turns'the 'plug 18 clockwise as shown in Fig. 4,

thereby making; the' 'connection between the openings 22 and 23 ``lairgjer"while' makin the connection between'the openin'g's 22 and" 2'4 smaller. The "amountoffwaterf flowing" away through opening 24 and pipe' 17- will then" be'reduced, and the* water 'level in the accumulator3 wlltherefore rise a`s' steam fed through the ejector 1 sscondensed in the water." With a' riing water level-,

the regulatng operation will he the oppositeg'that is`,`

the flow `through. the' opening 24 will ihcrease until equilihrium 'is 'reached "In this way the quantty of circulating 'heating' water is kept practiCallyco``sta1t` of heat n'the 'water'f While,^at `'the sametine, the lo's's flowing away is prevente'd.'

It Will be apparent' that in all of the illustrated embodinents of the" invention, the waterheater 1 (1 plateheater xchan ger 2 and punp 5 are connected 45 series'with and 'supported as aunit' on the acumulatprjj 3 whichjintur n, 'isjsip'prted on the frame26 testing upon"the floor. "This, all of these parts jare in eifectl supported 'in a unitary asseinblyby 'the name-26;

framefif' desired,'could"he' arrang'ed to directly su gj port one of the otler parts, such as the heatexchanger 2, "instead of the accumulatonf'lt' will also' be app areit r I citimin p'ump for the' hot water anda driving 4,: V flow pipe 4 of Fig. 1 each constitute a means for maintaining a substantially constant water level in the ac-' cumulator 3, by diverting from the circuit a quantity of water corresponding to that formed in the circu't by condensed steam from the ejector 1.

It will also be apparent that the part 3 not only serves as an accumnlatornthe circuitfm the hot water used in the plate hetexehangen but' also constitutes a holo hc ll tfi e t x h rl (the exchange: l E EL 1 and 3, or the exchanger 1 -2gimEig.. 2)., By virtue of this? arrangernen t t,ispos sihle.to red ce to a minimum the number of communications between' the set of e rt x hang plat s ds hes nz iarm pnatatusmf the system, partiularlywhen the part& also serves as a support for the motor-driven pump 5 of the hot water circuit, as illustrated.

conn'et'edio' the*'p`u`mp; the improvement'wherein I t the beat exchanger and the plate heater include :n plat'e packs which: together constitute a' plt Ht' ejchangenit, the; water a ccurnulatpr f ing an end wall nd"a support for'one end ofsaid co m plate hegat exchange' t, the pum'piard Inc' in`'r'imtedgn and supported by the lw'ergpo o o said ccuinlator,and "means "iterconnectingj the ac-jj a d l e hp a a ger'i d; he bl heatef'tofforrna "closed circulation path "for the w ter ZThelimprovement'ccordirrg to claim 1', in .whih the ccurnulator has 'ari overiiow outlet leadingifron j' inferior f'the aocumul'ator to the, outside thefeoii '3: The; imprbvment according to claim 1,; the accuinulatoi haswalls forinng a waterfrees inits`1o.w`

etew s d in the s of i at t i UNITED STATES PATENTS I;

Yarrovs( MayLL: 19.23

r portion; themotor having a, drive shaft 

